Developer documentationOverview
Once Email developer platform
Build reliable email test workflows
One place for the API contract, seven SDK ecosystems, versioned downloads, demos, and the open-source email test Skill.
Choose how you build
API
Public documentation · controlled access
Learn authentication, inbox operations, errors, limits, retries, and cleanup for authorized systems.
Read documentationSDK
Seven versioned prerelease SDKs
Download, verify, and build a fixed SDK release for the language already used by your test service.
Read documentationSkill
Open-source prerelease download
Add one bounded test to an authorized project, return redacted evidence, and always clean up.
Read documentationRecommended workflow
From contract to one clean test
Use one deadline and one uniquely marked message, then always clean up. Once Email receives mail only and does not automate third-party registration.
- 1
Confirm ownership or explicit authorization, then choose API, SDK, or Skill for the existing test stack.
- 2
Keep the API key in a process secret facility; verify every downloaded archive before use.
- 3
Run one bounded workflow and delete the temporary inbox in finally on success or failure.